Computational Fluid Dynamics Applied to Three-Dimensional Nonreacting Inviscid Flows in an Internal Combustion Engine

Abstract

The three-dimensional inviscid flowfield between the face of the piston and the top of the cylinder in a reciprocating internal combustion engine is calculated for a complete four-stroke cycle (intake, compression, power, exhaust). The fluid dynamic aspects are emphasized; combustion is simply modeled by constant-volume heat addition. The computational method is an explicit time-dependent finite-difference solution of the governing fluid dynamic equations. The results show that a well-defined three-dimensional swirling flow pattern is established during the intake stroke, and that this swirl persists throughout the complete four-stroke cycle. Such a flowfield will have direct influence on I.C. engine combustion phenomena. Moreover, the radial distributions of pressure and temperature show a nearly-axisymmetric behavior, while the three-dimensional results in the valve plane show a striking similarity to previous two-dimensional results. The present investigation is the first three-dimensional calculation of the flowfield for all four strokes, and has important implications for future work in the application of computational fluid dynamics to I. C. engine analysis.